At present, VCRs use different types of RF converters, namely, VHF converters and UHF converters. In Eastern and Western Europe using the PAL system, the RF output of the UHF output of a VHF converter can be varied from between 30 to 40 channels. The RF output of a VHF converter in Japan using the NTSC system has two channels: 1 and 2. The RF output of a VHF converter in Korea and the United States also has two channels: 3 and 4. Accordingly, the broadcasting channel may be the same as the RF output channel of a VCR in the area where the UHF band is employed so that a user can adjust the RF output to avoid mutual interference. That is, since the outgoing channel can be linearly varied in a UHF converter of a VCR, a test pattern which can serve as a reference for fine tuning is utilized by selecting one channel which is not utilized as the broadcasting channel in order to set (tune) the output of the VCR.
In a conventional UHF converter, the test pattern is formed using a test pattern generator. However, the addition of a test pattern generator increases the manufacturing cost.